Acute lymphoblastic leukemia in children: current status, controversies, and future perspective

Disease-free survival (DFS) in childhood ALL is 60%, and survival in good, average, and poor prognostic groups defined by initial WBC and age is 90, 60, and 45%, respectively. Additional immunological, morphological, biochemical, cytokinetic, and cytogenetic factors have been identified, illustrating the heterogeneity of ALL and its derivation from malignant clones at various stages of differentiation and with varying rates of proliferation. Of biologic importance, these factors may refine further the characteristic features of clinically-determined prognostic groups. Multivariate analysis of large prospective trials with homogeneous therapy will be required to determine the independent prognostic importance of these factors. Current treatment strategies in ALL include (1) tailoring therapy and its intensity to prognostic groups; (2) multiple-drug combinations in induction; (3) early use of intrathecal (IT) methotrexate (MTX); (4) CNS prophylaxis with IT MTX alone in good prognosis patients and combined cranial radiation (CXRT), 1800 rads plus IT MTX, in average and poor prognosis patients. Current studies show a CNS relapse rate of 5% in all prognostic groups. Late neuropsychological defects caused by cranial XRT and IT MTX have prompted programs designed to reduce the potential late toxicity of CNS prophylaxis. More pronounced in younger children, these abnormalities include decreased IQ, visual-motor incoordination, poor performance in mathematics, and memory dysfunction. Until 1980, more intensive induction, consolidation, and maintenance therapy had failed to prolong DFS in children with a poor prognosis. In West Germany (Berlin-Frankfurt-Muenster protocol) a 70 to 75% DFS is seen in all patients regardless of initial WBC, suggesting that effective therapy will override prognostic factors. Ultra-high-dose MTX, without cranial radiation, is also showing promise in poor prognosis patients. Other issues include the optimal duration of therapy, the role of testicular biopsies, and prophylactic testicular radiation. Recent studies suggest that prognostic factors lose their significance after 2 years of continuous complete remission and that 2 years of maintenance therapy is adequate. Bilateral open-wedge testicular biopsies have identified occult testicular disease in 8 to 10% of males. A unified approach to children with leukemia/lymphoma, a group with a particularly poor prognosis, utilizing NHL-type therapy may be more effective than conventional ALL therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Chronic L-DOPA-pretreatment of rats: an electrophysiological and biochemical study in the basal ganglia

Treatment of rats with L-DOPA (251.25 mg as the methyl ester HCl/kg) plus benserazide (B, 50 mg/kg) (L-DOPA+B), twice daily (i.p.) for 5 days or 12 days resulted in the dopamine (DA) neurons of the substantia nigra pars compacta becoming subsensitive to the rate-depressing effects of D-amphetamine (i.v.) 16 to 24 h after the last chronic drug dose. In contrast, pretreated rats were significantly less sensitive than control rats to the rate depressant effects of apomorphine (i.v.) after 12, but not 5 days of L-DOPA+B-pretreatment. After 5, but not 12 days of L-DOPA+B-pretreatment, a significant increase in the number of spontaneously active DA neurons was noted in the substantia nigra pars compacta. Caudate tyrosine hydroxylase was examined and a significant increase in apparent Vmax was noted after 5 days of L-DOPA+B, with no apparent change being noted in Km for cofactor. At this time, no change was noted in caudate DA or HVA concentrations. Several distinct processes may be occurring in response to the L-DOPA+B-pretreatment: (1) the DA autoreceptors located on cell bodies in the substantia nigra have become subsensitive after 12 days of L-DOPA+B-pretreatment; (2) the subsensitivity to D-amphetamine seen after both chronic schedules is probably unrelated to the subsensitive DA autoreceptors and may depend upon homeostatic alterations in neurotransmitter systems other than those utilising DA; (3) the activation of tyrosine hydroxylase may be a reflection of the increase in the number of spontaneously active units.

Granulocytic sarcoma of the clavicle

Acute myeloblastic leukemia is suspected usually because of abnormalities of the peripheral blood or bone marrow. In some cases there may also be an extramedullary focus of leukemic cells called a chloroma or granulocytic sarcoma. On occasion, these tumor masses may precede any evidence of leukemia by months or years. They are often misdiagnosed as lymphomas or granulomas. We present here a case of acute myeloblastic leukemia that was preceded by a granulocytic sarcoma of the clavicle. The initial biopsy of the clavicle was thought to be consistent with Ewing's sarcoma. The patient was treated with systemic chemotherapy prior to gross marrow involvement. He has been in continuous complete remission 34 months after the start of chemotherapy and 44 months after the development of granulocytic sarcoma.

Dural sinus thrombosis in children with acute lymphoblastic leukemia

Dural sinus thrombosis developed in two children with acute lymphoblastic leukemia during induction treatment with vincristine sulfate, prednisone, and asparaginase. Headache, nausea, emesis, and lethargy were the presenting signs. The diagnosis was confirmed by arteriography. The cause is presumed to be secondary to hypercoagulability due to asparaginase-induced antithrombin III deficiency. The patients received anticoagulation therapy and recovered completely. Only two of the six reported patients without heparinization survived.

Tetrahydrobiopterin in striatum: localization in dopamine nerve terminals and role in catecholamine synthesis

The hydroxylase cofactor, tetrahydrobiopterin, and its biosynthetic system are localized in dopaminergic nerve terminals in the striatum. This conclusion is based on the nearly equivalent loss of tyrosine hydroxylase and tetrahydrobiopterin and its initial biosynthetic enzyme, guanosine triphosphate cyclohydrolase, after injection of 6-hydroxydopamine into the substantia nigra. The role of the hydroxylase cofactor in the regulation of dopamine synthesis is reassessed.